Copper Alloys for Injection, Thermoform and Blow Molds

Copper Alloys for Injection, Thermoform and Blow Molds by Robert Kusner Manager of Technical Services June 2015

Today s Agenda History of copper mold alloys Why use copper? Which copper alloy should I use? Copper beryllium (C17200, MoldMAX High Hard ) MoldMAX Low Hard CuNi7SiCr (MoldMAX V, MoldStar 90, AMPCOLOY 944) MoldMAX XL PROTherm (C17510) C180 Aluminum bronze AMPCOLOY is a registered trade name of AMPCO METAL, SA MOLDSTAR is a registered trade name of Performance Alloys & Services, Inc. 2

Interesting Facts - Copper Mold Alloys 2 million pounds of copper alloys are used worldwide in the plastic tooling industry 1950s Cast copper beryllium molds were first used 1980s Wrought copper beryllium mold materials such as MoldMAX High Hard (C17200) Moderate strength non-beryllium copper mold alloys such as AMPCOLOY 940 (C18000) 2000s High strength, non-beryllium alloys such as AMPCOLOY 944, MoldMAX V and MoldMAX XL 3

4 Why Copper Mold Alloys?

Marks of a Good Mold Material #1. Strength Mold materials must be strong enough to withstand molding stresses. 5

Marks of a Good Mold Material #2. Machinability Mold material must be able to be machined using standard tools and equipment. 6

Marks of a Good Mold Material #3. Thermal Conductivity Mold materials must remove heat from the resins. 7

Why Copper? Copper mold alloys have 2-10 times the conductivity of mold steels After diamond and silver, copper is the most thermally conductive element. Productivity increases of 50% are common when steel is replaced with copper. Uniform cooling allows for the production of precision components that simply could not be made with steel. Uniform cooling eliminates condensation from over cooling mold. Leads to better surface finishes and saves energy. 8

Why Copper? 2. Copper alloys are gall resistant and can be used in moving components. 9

Why Copper? 3. Others benefits: Corrosion Resistant Biocidal Non-Magnetic Easily Machined 10

Why Copper - Caveats Copper is more costly than steel. Copper mold alloys have higher acquisition costs, but improved productivity and quality lead to more profit. Copper is not as stiff as steel (Bulk Modulus) However, it does make a better spring than steel. Copper will bend a lot further than steel without breaking or deforming. Copper is intrinsically weaker than steel (UTS and Yield Strength). Requires elaborate metallurgy or coatings to match steel s performance. Copper has a higher thermal expansion than steel 11

Copper Mold Alloy Applications Core/cavities and inserts, injection/blow molds Core pins and ejector pins Blow mold pinch offs Slides and moving components Hot runner nozzles Sprue bushings Injection press bushings and wear pads 12

Choosing a Copper Alloy Three Little Pigs Emperor s New Clothes The Hindenburg Choosing the wrong material can be disastrous! 13

Thermal Conductivity Rating (P-20 =1) Choosing a Copper Alloy Mold Alloy Hardness vs. Conductivity 9 8 PROTherm C17510 CuNiBe 7 C18000 CuNiSiCr 14 6 5 4 3 2 1 0 QC 10 C954 Al Bronz MoldMAX V CuNi7SiCr MoldMAX LH C17200 LH CuBe2 MoldMAX HH C17200 HH CuBe2 MoldMAX XL CuNi9Sn6 AMPCOLOY M4 P-20 H-13 420 SS 0 100 200 300 400 500 600 Brinell Hardness (HB)

How to Strengthen Copper Copper in its pure form is weak with a tensile strength about 5 times lower than steel. There are 2 ways to strengthen copper (these can be used in tandem). Cold work (rolling, drawing or hammering) Alloying May or may not include heat treatments for phase transformations 15

How to Strengthen Copper Strengthening mechanisms require disturbing the atomic lattice to arrest dislocation glide 16

Selection of Mold Alloy Is mold unproductive? Does mold run hot? Does mold cool unevenly? Yes No Continue to use steel mold alloy. 17

Selection of a Mold Alloy Hot mold Is mold exposed to high molding stresses? Yes No Use a moderate strength copper alloy: C17510 or C180 18

Selection of a Mold Alloy High Stresses Are there any material restrictions by specifier? No Yes Use high strength CuNi7SiCr, MMXL 19

C17200 Copper Beryllium aka MoldMAX HH, MoldMAX LH, Alloy 25, CuBe2, AMPCOLOY 83 98% Copper, 1.8% Beryllium and 0.2% Cobalt MoldMAX High Hard (HH) Highest hardness of any copper mold alloy (36-42 HRC). Good conductivity, more than 4 times that of mold steels. Readily available in many sizes and shapes. After heat treatment, it has 5 times the strength of pure copper with 30% of coppers conductivity. Purchase and machine in heat treated, hardened state. 20

C17200 Copper Beryllium MoldMAX Low Hard MoldMAX LH is available with 20% more conductivity, twice the impact fracture resistance, but 25% less strength. The hardest copper next to High Hard. 21

C17200 Copper Beryllium Microstructures Microstructures from High Quality Wrought Plates or Bars 22

C17200 Copper Beryllium Microstructures Microstructures from low Quality Wrought Plates or Bars C17200 with remnant cast structure C17200 with beta phase inclusion 23

C17200 Copper Beryllium: Health and Safety Copper beryllium (CuBe), in solid form and as contained in finished products, presents no special health risks. However, like many industrial materials, copper beryllium may present a health risk if handled improperly. The inhalation of dust, mist or fume containing beryllium can cause a serious lung condition in some individuals. No government entity has banned or placed restrictions on the use of copper beryllium in the molding industry. Testing of food container plastics molded with copper beryllium revealed no transfer of beryllium to the molded part surface. 24

C17200 Copper Beryllium: Health and Safety Copper beryllium can be fabricated safely by employing the Beryllium Worker Protection Model: See http://www.berylliumsafety.com/ Additional information on the safe use and handling of copper beryllium alloys, including Safety Facts, FAQ s and Safety Data Sheets are available in the Environmental Health and Safety Resource Center at http://www.materion.com. If you have specific questions regarding the safe use and handling of copper beryllium alloys, please contact the Materion Product Stewardship Group at 1-800-862-4118. 25

Selection of a Mold Alloy High Stresses Are there any material restrictions by specifier? Yes No Use C17200 MoldMAX High Hard or Low Hard 26

Selection of a Mold Alloy High Stress, Material Restrictions Is large section thickness or high surface polish required? No Yes Use MoldMAX XL 27

CuNi7SiCr 28 aka MoldMAX V, AMPOCOLOY 944, MoldStar 90 90% Copper, 7% Nickel, 2% Si, 1% Chromium Very good conductivity, 5 times that of P-20 ( 90 Btu/ft-hr- F ) Capable of achieving hardness up to about 30 HRC, but normally around 26 HRC. Very difficult to manufacture in thick sections. Normally available in thickness up to about 4. Provides good wear resistance. Related to the large numbers of nickel silicide particles in the metal. Polishability is limited by large nickel silicide phases.

CuNi7SiCr CuNi7SiCr microstructure. Gray areas are Nickel Silicide. 29

Selection of a Mold Alloy High Stress, Material Restrictions Is large section thickness or high surface polish required? Yes No Use CuNi7SiCr 30

MoldMAX XL 85% Copper, 9% Nickel and 6% Tin Available in section thickness to 12. More than twice the conductivity of P-20, 40 BTU/hr-ft- F Good hardness of 28-32 HRC. Good fracture resistance (typically >10 ft-lbs) in large section plates. Excellent galling resistance and wear resistance. Supports lens mold quality surface finish in both large section Equicast plate and smaller extruded rod. 31

MoldMAX XL Microstructure of large section plate Microstructure of extruded rod 32

Selection of a Mold Alloy Hot mold Is mold exposed to high molding stresses? No Yes Use MoldMAX HH, LH (C17200), MMXL or CuNi7SiCr 33

C17510 (PROTherm) and C180 CuNiSiCr C17510: 98% Cu, 1.4% Ni and 0.3% Be C18000: 96.5% Cu, 2.5% Ni, 0.5% Si and 0.5% Cr Widely used in blow molds. Conductivity in excess of 120 BTU/hr-ft- F (210 W/m-K). Hardness 92-99 HRB. C17510 copper beryllium has 10-20% higher strength and conductivity than C180 and better ductility. Stable at temperatures in excess of 800 F, although there is a loss of strength and ductility. 34

C 17510 PROtherm and C180 C180 PROTherm 35

Other Copper Alloys Aluminum bronze is a low-cost copper alloy sometimes used in mold tooling. Marginally more conductive than steel with insufficient hardness for more demanding molding applications. The gall resistance of aluminum bronze makes it a low cost alternative for sliding components. Aluminum bronzes are widely used as bushings on injection presses. Unique among coppers in that they are strengthened by Martensitic transformation. 36

37 Aluminum Bronzes

In Summary Copper mold alloys are primarily used when a steel mold gets too hot or unevenly hot, leading to long cycle time and poor part quality. Other reasons are gall resistance, corrosion resistance, bio resistance and magnetic neutrality. C17200, such as MoldMAX High Hard, is the copper alloy of choice for injection molding applications. It has the best balance of conductivity and hardness. In the event that copper beryllium can t be used, CuNi7CrSi (MoldMAX V, MoldStar 90, AMPCOLOY 944) and MoldMAX XL are the best option. There are no governmental bans on the use of copper beryllium molds. 38

In Summary, continued C17510 PROTherm and C180 are high conductivity, moderate hardness copper mold alloys primarily used in blow molds and some injection mold caps. Aluminum bronze is a low cost copper alloy that finds use in wear and gall resistance applications. It is only moderately more conductive than mold steels. Copper mold alloys have a long history of solving problems in the injection molding industry. It will continue to be inserted into molds as there is no other practical material that can provide the same combination of hardness and conductivity. 39

Questions? Materion Performance Alloys Technical Support 1.800.375.4205 Or Materion.com/moldmax www.berylliumsafety.com 40